Each user can make changes to configurations related to their own account or devices (phones). To change other settings, such as Room Phone names, or recording a Main Line Greeting, your account must have Office Admin privileges.
In most schools, parishes, and offices, there is at least one person who has Office Admin privileges - typically a principal, office manager, or receptionist. You can determine if your account has Office Admin privileges by logging in at https://dialpad.com, and looking in the blue bar on the left side; if you see a cog wheel icon, then you have Office Admin privileges. Click that icon to access the Admin Settings for your office.
If you are logged into the Admin Settings and you click Users, any user name in the list that has a green Admin icon next to their name has Office Admin privileges.